Motor vehicle driving mechanism



June 8, 1954 K. MAYBACH MOTOR VEHICLE DRIVING MECHANISM 2 Sheets-Sheet 1Filed Dec. 28, 1949 TeANsM lssnoN June 8, 1954 K. MAYBACH 2,680,381MOTOR VEHICLE DRIVING MEcHANIsM Filed Dec. 28, 1949 2 Sheets-Sheet 2DIESEL.

ENG\NE FUE'. Pump d; 103

Patented June 8, 1954 2,680,381 MOTOR VEHICLE DRIVING MECHANISM KarlMaybach, Friedrichshafen, Germany Application December 28, 1949, SerialNo. 135,404

Claims priority, application Germany December 30, 1948 5 Claims. 1

This invention concerns a mechanism for regulating the fuel supply to aninternal combustion engine having an automatic gear change mechanismconnected with the engine, and comprising an additional mechanism forvarying the engine speed (R. P. M.) at which a gear change is effected,in such relation to the power output variations of the driving engine,that the engine speed at which automatic gear change is effected isgreater when the output of the engine is greater.

The aforesaid additional mechanism was recently introduced in powervehicles for the purpose of lowering the number of revolutions of theengine required for a given distance travelled by the vehicle, so as toreduce wear and tear of the engine and to reduce fuel consumption whenrunning on part load.

The invention is especially intended for use in power vehicles for heavyloads and having relatively large rotating masses. With this type ofvehicle, the driver is unable to judge by ear the running of the engine,and, even if this were possible, continuous observation of the runningof the engine and frequent gear changes cannot be expected of thevehicle driver. Even a highly skilled driverV would not shift the gearsat the most favourable moments. The vehicles for which the invention hasspecial advantages are locomotives, motorized railway cars, tramways,

large omnibuses and the like. With such vehicles automatic gear changingmechanisms are a necessity because, for example with a large townomnibus, several thousand gear changes are necessary each day. Up tillnow, however, automatic gear change mechanisms could not be introducedto any large extent on these vehicles primarily because, without theadditional mechanism mentioned above for adjusting the engine speed atwhich gear change occurs correspondingly to the load, the engineoperates on part load at an unnecessarily high speed.

This can usually be corrected on street vehicles by the vehicle driverby means of gear changing since he notices the high engine speed by thenoise of the engine. With many vehicles, however, and especially withrail vehicles, this is not possible. If the engine speed at which gearchange occurs is changed correspondingly to the load, no additional gearchanges by the driver are required. Gear shifting is effected at thecorrect moment and much more accurately than by the most experienceddriver.

On a vehicle comprising a mechanism for the variation of the gear changespeeds and an autolla matic gear changing mechanism, the driver isrelieved of gear changing and fuel consumption as well as wear isreduced because of the reduced engine revolutions per kilometretravelled. In such vehicles, if, for example when operating with thefourth speed gear of six gears the vehicle driver closes the throttleand thereby automatically lowers the gear ratio, shifting to higherspeed gear is immediately eifected by the automatic gear changemechanism and the engine `speed is correspondingly lowered. If thevehicle driver opens the throttle, shifting to lower speed gears isautomatically effected until the vehicle travels again in the previouslyused gear and with the previous engine performance.

The. result of this is that, for example with locomotives or motorizedrailway cars which are quickly passing through switches into stations,or with street vehicles running on short descending sections, upwardgear changes would be induced by the automatic gear changing mechanismwhich, shortly afterwards, must be changed downwards again. Also, forexample, with omnibuses with short reductions of engine performance intraine for the purpose of overtaking or braking and immediatelythereafter again increasing the output of the engine, upward gearchangings and shortly following thereafter downward gear changings arenot desired. .By means of the regulating mechanism according to theinvention these disadvantages are avoided and, whilst completelyretaining the automatic operation, gear changes which are not necessaryare prevented, so that as in a vehicle with manual gear shifting meansoperation in the previous gear is instantly resumed at the previouslyused most favourable engine speed and performance when the throttle isagain opened.

According to the invention a mechanism is provided which, upon reductionof the driving power, blocks the mechanism for varying theengine speedat which gear change occurs.

A delaying .mechanism is preferably arranged in combination with themechanism for the variation of the gear change speeds for delaying theactuation of the mechanism for the variation of the'gear change speedsupon reduction of the engine output. This is of particular importance,for example, for omnibuses.

For rail vehicles and street vehicles operating under similar drivingconditions it is advantageous to provide a mechanism for changing theoutput of the engine and for simultaneously changing the gear shiftingspeeds, together with a mechanism for solely changing the driving powerwithout simultaneous variation of the gear change speeds. This lattermechanism can also be so constructed that it produces temporary blockingor (in `combination with a retarding mechanism) delay of the variationof the gear change speeds. At temporarily necessary relatively shortlthrottling operations the former mechanism is left unchanged, which isespecially desirable with mechanisms which require, for example, manyrevolutions of a hand wheel for disconnecting, and only the secondmechanism is returned to its zero position. Thereby the gear changespeeds are not changed. On opening the throttle again, the previous gearspeed, engine speed, and driving power are available.

The invention will be further described by way of example with referenceto the accompanying drawings in which:

Fig. 1 is a diagrammatic part sectional illustration of a regulatingmechanism according to the invention for a street vehicle.

Fig. 2 is a diagrammatic illustration of a regulating mechanismaccording to the invention for a rail vehicle (locomotive or motorizedrail car).

Referring to Fig. l, numeral I designates a diesel engine having a fuelpump 2. The diesel engine drives a change speed gear transmission in agearbox 4 by means of a shaft 3, the gear changes of the transmissionbeing effected by means of pressure oil cylinders 5 and c. The output,shaft I of the transmission drives the vehicle axlesby means, not shown.Numerals 8, S and I3 designate spur gear wheels driving centrifugalgovernors -II and I2 decreasing and inu creasing the gear ratio of thetransmission. These governors actuate displaceable slide valves I3 andI4 in housings I5 and I5 against the pressure of springs I1 and I3respectively. Valves I3 and tf1 have narrow portions |9 `and 2e,respectively. Pressure oil supplied through a conduit 2 2 is conductedto the housings I5and I6 through conduits 23 and 24 respectively.Pressure oil controlled by the slide valves I3 and I4 is conductedthrough conduits 25 and 26 to'cylinders 21 and 28, respectively, insideof whichpistons (not illustrated) operate by means of rods and pawlsratchet wheels 2S and 3U which revolve a cam shaft 3| projecting from ahousing 32. Numeral carries a roller itl'.

4 in a suitable cross-guide 54 on the end of a piston rod 65.

65 is a valve housing, forming a chamber the interior of which isconnected by means of an opening 6i with the lower part of the interiorof a cylinder lo, the upper wall of housing 66 being provided with achannel 'H which is closed by a valve $39 pressed thereagainst by spring63. The valve Se has a throttle orifice E3. Above the valve housing @Eis an oil reservoir 'i2 which is .connected to the outside at upper endthrough an opening i3.

A piston i4. slides in the cylinder' 1B which is lled with oil, pistoni4 being connected with `the Vlever 5|! by means of a rod G5. Alongitudinal bore 'I5 and a cross bore i5 are arranged in the piston"|4. The upper end of the longitudinal bore '|5 extends through a valveseat which is closed by a plate valve '16. The valve i3 is in a housing'i8 on the head side or piston i4. Its stroke is limited by an abutmenti S.

Numeral 85 `glesignates a cylinder in which a slide valve 8|isidisplaceable against the pressure of a spring 32. 83 is an openingconnecting the housing 33 to the outside. Numeral 84 designates a portconnecting the interior of the cylinder 80 with a compartment 35disposed thereabove. A valve Sii having a throttle opening 88 is pressedagainst the upper wall of compartment 85 by a spring 8i for closing anaperture 83 in said upper wall. Aperture 83 communicates with atransverse channel QG communicating with a longitudinal channel 9 i. Theinterior of the cylinder 8l) is connected with the channel 9| by meansof an aperture 92 and with the interior of the .cylinder 'lo by means ofa port 33.

In Fig, 2 numeral to2 designates the fuel pump of a diesel engine I 0i,the control of the fuel pump being effected through a lever i to which arod |34 is pivoted. The latter is connected with a lever |05 which isconnected to a lever |06 and is dra-wn upwardly by means of a tensionspring |38. A plate i3? is disposed at the free end of the lever |35.The end of the lever |06 |59 is a hand wheel which i' can be turned bythe vehicle driver by ineens of 33 designates a conduit supplying apressure fluid to the control housing 32, which is Aconnected byconduits 35, 3i, 38 to the gear change cylin\ ders 5 and Numeral 4,0designates a foot lever which is pulled by a spring 39 against anabutment 4I and on the swing axis vof which a disc ,42 is arranged. Thelatter is provided with two cams 43 and 44. The dotted lines 40 show thefoot lever 4D, in rest position corresponding to the positions 43 and4.4 of the cams 43 and 44. Rollers 45 and 46 .bearing against the cams43 and 44 are mounted o n levers 4T and 48 with which levers 49 and 50,respectively, are connected. Tension springs 5I .and 52 tend to pull thelevers 49 and the positions indicated by dotted lines 41', 48', 49 .and.50 corresponding to the position 4.0 of the foot lever. 53 is aconnecting rod between the lever 49 and a Ylever 54 disposed on theregulating shaft .of the fuel pump 2. 55 'is a rod pivoted to the lever50, the lower end of which is connected with levers 51 and 58, 7o

which individually engage an end surface of pistons 3| and 52 throughfingers 5B and 6|), respectively. Springs |1 and I8 abut against theother end surfaces of the pistons 6| and 62- A pin 63 disposed at thefree end of the lever 50 is slidable 75 a handle H3 and on the axis ofwhich a small chain wheel iII is arranged from which, by way of Va chainI I2, a large chain wheel l i3 isY driven. Wheel I|3 is mounted on anaxle lic together with two cams H5 and H6. The roller |37 of the lever55 bears on the cam HE, a roller llt mounted on a lever iii bearingagainst the cam IIS. The lever iii is connected with a lever H9 to whichthe rod 55 is pivoted, lever H3 being pulled upwardly by means of aspring |2| so that the roller ||8 is always pressed against the cam H6.The positions of the cams H5 and |16 shown in dotted lines H5 and H3correspond tothe smallest output ofthe fuel pump |82.

Numeral |30 designates a hand lever which is held against an abutment|32 by means of a spring |3I. The lever |33 has a slot |33 in which apin |34 at the end of a rod |35 is guided. A knob |36 is provided at theother end of the rod. Referring to Fig. 1, while the vehicle is movingand the foot lever 43 is in the position drawn in full lines whichcorresponds at the corresponding position of the cam 43 and of thelevers el' and 49 to an output of the fuel pump 2 of aboutthree-quarters of its maximum output. The diesel engine operates atsomewhat below its maximum speed. Cam 44 is also in the position drawnin full lines and the adjusting levers 48 and 50 are also in thepositions indicated in full lines. The ngers 59 and 60 are held by meansof the levers 51 and 58 and rod 55 in the position shown in full linesand the force exerted by the springs and I8 on the pistons 6| and 62 isgreater than the force exerted when the device was in the position shownin dotted lines. The speed of rotation of the shaft 3 at which theautomatic gear changing mechanism in the housing 32 is actuated by thegovernors and |2 is, therefore, increased corresponding to the selectedpower output.

The cylinder 19 is filled with oil above and below the piston 14 as alsoare the channels 99 and 9|, the valve housings 66 and B5 and thecylinder 'l2 approximately to the illustrated level.

On movement of the lever and of the adjusting rod for the speedgovernors and |2 in a downward direction, the piston |4,` arranged inthe cylinder l0, is moved down from its upper end position whereby thevalve 16 is unseated due to the reduced oil pressure below the valve andoil escapes upwardly from the space below the piston 14 through thepassage formed by the bores |5 and 15. The valve 86 remains closedbecause the spring does not permit opening until a certain excesspressure obtains above the piston 'M The piston 8| remains in theillustrated position since a pressure which is not sufcient to overcomethe tension of the spring 82 acts against its upper' end surface..

If the vehicle driver releases the foot lever 49 to move it into theposition 40', the cam 43 moves to the position 43' and the lever 41moves to the position 41. Upon movement of the lever 49 to the position49 the rod 53 and the lever 54 on the fuel pump is brought into theposition 54'. The fuel pumpl 2 is set thereby for smallest fueldelivery.

At this operation the cam 44 attains the position 44. However, thelevers 48 and 59 do not follow this movement since the piston 14 in thecylinder T9 connected therewith cannot move upwardly because the valvei6 remains closed, the smallest upward uoveinent of the piston l@causing an extraordinarily high pressure in the oil above the pistonwhich opposes the movement of the piston. This pressure propagates intothe spaces and 9| and opens the valve S5 affording oil iow inside of thehousing 85 and through the opening 84 in the space of the housing S9above piston 8|. Thereby the piston 8| is pressed downwardlycorresponding to the amount of fluid slowly passing through the valve86. Thereby the piston 14 is downwardly displaced correspending to theamount of uid discharged `from the interior of the cylinder 'I9 into thespace l above the slide valve 8 Due to the suction effect below thepiston i4, the valve 69 opens and so much oil is allowed to pass out ofthe interior of the cylinder 'i2 as space is provided by the movement ofthe piston 74. y

If the vehicle driver does not reopen the throttle, after some time, forexample after ten seconds, the piston 3| provides a free passage for theoil contained in the channel 9| through the'openings 92 and 93.

Thereby oil, due to the excess pressure obtaining above the piston 'ifiis conducted into the interior of the cylinder 'lo below the piston 14.The piston 'i4 now moves upwardly due to the pressure of spring 52. Therods 55 Vand 55, the levers 55 and 48, 51 and 5 9 and the iingers 59 and69 can now move toward the positions shown in dotted lines. The pistons5| and 52 follow the fingers due to expansion of the springs and |8 andthereby the gear changing speeds are reduced speeds therefore remainunchanged.

" substantially.

to a value corresponding to the position of the lever 48 bearingagainstthe cam 44 in the position 48. Gear changes are now effected inthe gear box by means of the automaticrgear changing mechanism.

If the vehicle driver again opens the throttle, the lever 4'! as well asthe lever 43 follow the cams 43 and 44. The movement of the levers 48and 59 and of the rods 55 and 55 together with the downward movement ofthe piston 'I4 is not restrained since the valve i5 allows the oil topass from the lower to the upper side of the piston 14. Simultaneouslyalso, the oil from the space above the slide valve 8| returning upwardlyby the action of the spring 82 is urged back through the throttle bore88 and the surplus oil in the system passes back through the throttlebore 69 into the interior of the oil reservoir l2. Thus the originalcondition of the delay mechanism is reproduced. In the embodiment shownin Fig. 2 several clockwise revolutions of the hand wheel |09 arenecessary to change the fuel control mechanism from the zero positionshown by dashed lines to the position for maximum delivery rate of thefuel pump |92 because of the ratio of the transmission H2, ||3. Theshaft I|4 is r0- tated about three quarters of a revolution during theaforesaid operation, the required delivery rate of the fuel pump beingadjusted by means of the leversy |05 and |95, the rod |04 and the lever|93. Simultaneously with the setting of the fuel pump the levers I1 andH9 are moved from the dashed line position to the position shown in fulllines by means of the cam H6. The gear changing speeds corresponding tothe selected' engine output are increased by means ofthe rod 55 insimilar manner to that of the embodiment shown in Fig. l. If the vehicledriver wishes to lower the engine output for a short time only andthereby gear changes are not desired, he presses the lever |35downwards. The lever |95 is thereby moved downwardly by the knob |36 ofthe rod |35 as a result of which the lever |95 is pulled away from thecam H5 and the levers |08, and |93 attain the position drawn dashed|95', |95', |03 shown in dashed lines. The fuel pump m2 is thereby setfor light running, The levers ||2l and H9 and the rod 55 remainconnected to the cam IIS and the gear change The vehicle driver canobtain the previously used setting of the fuel pump by releasing thehand lever i3@ as soon as this is permitted by the road conditions. Forthe whole time during which the vehicle was run with reduced engineoutput the gear change speeds remained unchanged. at their originallyselected value. Therefore no gear changes take place in the gear box aslong as the speed of travel does not fall I claim:

1. A fuel supply and power transmission con-l latter when connectedthereto and connected with said speed responsive means for adjusting theeffect of the latter on said change speed gear control means, andautomatic action delaying means connected with said adjusting means fordelaying the action of the latter on said speed responsive means upon areduction of the fuel Supply.

'2. A system as defined in claim 1 in which said delaying means comprisea rst cylinder, a piston reciprocable in said iirst cylinder, a pistonrod connecting said piston with said adjusting means, a passage in saidpiston connecting the spaces of said rst cylinder at both sides of saidpiston, a valve in said passage adapted to close said passage uponmovement of said piston and of said adjusting means connected thereto inone direction and to open said passage upon movement of said piston andof said adjusting,f means in the opposite direction, a compartmenthaving an aperture communicating with the space in said first cylinderon the head side of said piston, a spring loaded valve in saidcompartment for closing said aperture, a sec-ond cylinder, communicatingwith the interior of said compartment, a spring actuated slide valve insaid second cylinder, a port controlled by said slide valve connectingthe interior of said second cylinder with the space in said rst cylinderon the piston rod side of said piston, an aperture controlled by saidslide valve in said second cylinder, a channel connecting said firstcylinder with said aperture, a chamber communicating with the space ofsaid rst cyln inder on the piston rod side of said piston, a reservoir,a channel connecting said reservoir With said chamber, a spring loadedvalve in said chamber for closing said channel, a throttling orifice insaid last mentioned valve connecting said chamber with said channel, anda liquid filling said cylinders, said compartment, said chamber, andsaid reservoir.

3. A fuel supply and power transmission control system for vehiclesdriven by an internal combustion engine, comprising, in combination,

fuel supply control means for controlling the fuel supply to the engine,actuating means for said fuel supply control means, a change speed geartransmission driven by the internal combusticn engine, change speed gearcontrol means connected with said transmission, adjustable speedresponsive means connectedwith and being responsive to the operatingspeed of the internal combustion engine and connected with said changespeed gear control means for actuating the latter, adjusting meansconnectable with said iuel supply control actuating means and connectedwith said speed responsive means for adjusting the speed at which theyrespond for actuating said change speed gear control means, and amechanism adapted to connect said adjusting means to said actuatingmeans for said fuel supply control means for actuation of said adjustingmeans by said actuating means, said mechanism comprising delaying meansaffording .substantially Unresisted connection of said adjusting meansWith said fuel supply control actuating means upon movement of saidadjusting means in a direction for increasing the responsive speed ofsaid speed responsive means and resisting connection of said adjustingmeans with said fuel supply control actuating means upon movement ofsaid adjusting means in the oppo-Y site direction,

4. A fuel supply and power transmission control system for vehiclesdriven by an internal combustion engine, comprising, in combination,fuel supply control means for controlling the fuel supply to the engine,actuating means for said fuel supply control means, a change speed geartransmission driven by the internal combustion engine, change speed gearcontrol means connected with said transmission, adjustable speedresponsive means connected with and being responsive to the operatingspeed of the internal combustion engine and connected with said changespeed gear control means for actuating the latter, adjusting meansconnected with said actuating means for the fuel supply control meansand with said speed responsive means for adjusting the speed at whichthey actuate said change speed gear control means, and an additionalactuating device for said fuel supply control means adapted to actuatesaid fuel supply control means independently of said actuating means andWithout affecting said adjusting means.

5. A fuel supply and power transmission control system for vehiclesdriven by an internal combustion engine, comprising, in combination,fuel supply ycontrol means for controlling the fuel supply to theengine, actuating means for said fuel supply control means, a changespeed gear transmission driven by the internal combustion engine, changespeed gear control means connected with said transmission, adjustablespeed responsive means connected with and being responsive to theoperating speed of the internal combustion engine and connected withsaid change speed gear control means for actuating the latter, adjustingmeans connectable with said fuel supply control means and connected withsaid speed responsive means for adjusting the speed at which said speedresponsive means respond for actuating said change speed gear controlmeans, a mechanism adapted to connect said adjusting means to saidactuating means for said fuel supply control means for actuation of saidadjusting means by said actuating means, and means temporarilyinterrupting connection of said adjusting means with said actuatingmeans when the latter are suddenly moved in a direction for reducing thefuel supply.

References Cited in the file of this patent UNITED STATES PATENTSNurnber Name Date 905,637 Beslrow Dec, l, i908 1,882,805 Gillett Oct.18, 1932 2,071,785 Ehrlich Feb. 23, 1937 2,089,590 Walti Aug. 10, 19372,136,760 Saives Nov. 15, 1938 2,207,481 Derungs July 9, 1940 2,330,581Hefel Sept. 28, 1943 2,352,212 Lang June 27, 1944 2,411,463 PoZga-y Nov.19, 1946 FOREIGN PATENTS Number Country Date 875,016 France Sept. 3,1942 889,074 France Dec. 30, 1943 890,868 France Feb. 21, 1944

